The uplink and downlink pre-coding method based on the codebook is a very important technology. The design of the uplink and downlink codebooks can greatly enhance the performance of the uplink and downlink.
In the new generation cellular radio mobile communication system, a matured downlink pre-coding method based on the codebook is available. However, no solution has been proposed for the uplink pre-coding method based on the codebook, where the uplink pre-coding method can improve the uplink throughput. To compensate this deficiency, the current solution is to use the downlink codebook directly as the uplink codebook to perform pre-coding.
However, to use the downlink codebook directly as the uplink codebook to perform pre-coding may increase power loss of the power amplifier